trans bolts missing - wth?

[saylor]

I was down under the passenger side scrounging around with the front end work, and noticed that this spot on the transmission is missing a couple of bolts.
anyone know the size / spec on these so I can get more? are they all the same like I could pull one out and go match it at the store?

- saylor

 

[Stormer]

They're all the same.

 

[BJS racing]

They should be 5/16 coarse thread bolts about 1/2" long if I remember correctly. And every car I have ever worked on had those missing because someone was to lazy to put them in.

 

[commando1]

Or because the holes were stripped.........

 

[polara71]

Those dont usually get stripped, no one tightens those that hard..... Usually they are left out on purpose.....and get lost

 

[commando1]

We're in two different universes then. I see those inspection plate bolt holes stripped a lot in my universe.
And tranny pan cover bolt holes....

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[polara71]

Theres a reason the pan bolts strip. Because when the trans leaks people over tighten the bolt and strip the threads or snap the head. There is no reason to crank down these bolts enough to strip them

 

[saylor]

thx for the help people. im from commandos world, but i hope we are wrong. when i see a bolt missing i got to wonder if its stripped, or was cross threaded. especially header bolts.
ill get some and stab em in and see what we got.

 

[Gerald Morris]

Apropos of stripped tranny bolts, I goobered a pan bolt on my 727 this evening, yet had not even clicked the 12.5 ft*lb setting I had on the torque wrench as I was tightening it along with all the others securing a new stamped steel pan (Taiwan, yeah, I know....) with the MOPAR 02464324AC I threw down on to assure that at least the gasket was the best I could get for the $$. Anyway, what is the prevailing wisdom w.r.t. fixing such disasters? Should I carefully drill and tap a 3/8 x 16 hole, or try tapping the existing 5/16" x 18 again? Dare I add 1/4" more depth to the hole, THEN tap THAT? Any experienced perspectives are welcome here. Pardon me for exploiting another man's thread, but I hope at least my query is relevant or topical.

 

[jake]

When I got my car, two of the bolts in the pan were missing. The guy stripped them out. I drilled and tap for the 3/8x16. No problem at all.

 

[twostick]

The "correct" way to repair that would be to drill and tap to install a Helicoil and use the original 5/16 bolt.

Kevin

 

[commando1]

The "correct" way to repair that would be to drill and tap to install a Helicoil and use the original 5/16 bolt.

Kevin

Not only the correct way but the only way.

Threaded aluminum. WTF were they thinking?

 

[jake]

I believe you are removing more material drilling the helicoil, if I remember right. Thats why I tapped for 3/8ths.

 

[68Nwprt]

For the record I believe those are 1/4-20 x 1/2 Hex head bolt.

 

[twostick]

I believe you are removing more material drilling the helicoil, if I remember right. Thats why I tapped for 3/8ths.

You do drill it bigger but not as big as a 3/8 tap needs.

Kevin

 

[68Nwprt]

17/64 (.265) drill for 1/4 -20 heli coil. Drill, tap, and helicoil should come as a set.
Tap Chart Helicoil Threads

 

[jake]

I think pan bolts are 5/16ths. Inspection bolts are 1/4. I would have to go out and verify. I believe a 5/16ths helicoil hole is the same as a 3/8x16 bolt. Either way, like Commando said, threads in Aluminum, WTF.

 

[saylor]

damn.

mine are prolly still missing, I didn't ever try to put any back. unless the xmission guy put some in... but good luck with your repair.

the only time I ever used a heli coil was on exhaust header bolt, but it worked perfectly.

try not to die -

- saylor

 

[jake]

My pan bolts are 5/16ths. Helicoid of that size is a drill bit of 21/64 and a 3/8thz bolt is 20/64ths. They have not learned there lesson because I had issues with my 09 ram and the aluminum heads. I was lucky and was able to get out exhaust bolts that snapped off. Engineers!!

 

[68Nwprt]

I think pan bolts are 5/16ths. Inspection bolts are 1/4. I would have to go out and verify. I believe a 5/16ths helicoil hole is the same as a 3/8x16 bolt. Either way, like Commando said, threads in Aluminum, WTF.

From the photo it appears to be the inspection cover bolt that's missing.